I have a Jotul F602, with a 5" flue collar that I need to connect to a 6" chimney liner. I know I'll need a 5"-6" increaser, but am wondering if the increaser needs to be attached right to the flue collar, or if I can run a 5" pipe off the collar, and put the increaser at the top of that 5" piece, connecting it to a 6" elbow that makes the turn toward the chimney? I'm very much a newbie, so any insights will be really appreciated! Thank